This study had limitations. First, the purpose of the study was to
investigate the relationship between sleep and depression; therefore, the effects antidepressants exert on sleep were not addressed.
Second, the findings are limited because only inpatients were observed; thus, the results regarding sleep disturbance are not applicable to outpatients. Third, the subjective sleep and objective sleep
variables were only partially correlated, possibly because a sleep
log was used. Patients' recordings of subjective sleep data may
have been influenced by their depression, and therefore, the reported sleep quality may have been biased. Fourth, the study participants
were patients with depression; a study demonstrated that people at
a high risk of depression have negative biases when processing information (Nolen-Hoeksema & Hilt, 2008). Therefore, the subjective
information obtained may not have been as accurate as the objective
data. Lastly, the study participants were Taiwanese and all questionnaires were Chinese versions. If a similar study were conducted in
other countries, results may vary because of cultural differences. Future research should investigate the effects antidepressants exert on
sleep, include outpatients, or not limit the sleep data. These suggestions may facilitate future research pertaining to sleep disturbances
and other sleep-quality-related information.